Fuel injector



Aug. 14, 1945. w. HARPER, JR

FUEL INJECTOR I Filed Dec. ll, 1940 /V Q w M W w ,m q/ w l INVENTOR Nimm Harp" BY ELTLI, (LNILMM ATTORNEYS reuma Au.14,1a4s

UNITED STATES PATENT OFFICE FUEL INJECTOB William Harper, Jr., Montreal, Quebec, Canada Application December 11, 1940,` Serial No. 369,582

4 Claims.

This invention relates to fuel injectors and aims to provide an improved fuel injector nozzle for internal combustion engines.

Fuel injectors used commonly with internal combustion engines in the past include those Drovided with the so-called pintle type of spray nozzle and those provided with the so-called hole" type of spray nozzle. In neither of these has it been found possible to obtain satisfactory admixture of fuel particles with air in an engine cylinder without having the fuel particles impinge upon the walls of the engine cylinder, in which event the fuel condenses upon those walls rendering it useless as fuel for the engine, or having the fuel particles strike hot spots on the piston head causing pre-ignition. These disadvantages are due to the fact that pastA injectors equipped with the pintle type nozzle direct fuel toward the walls ofthe engine cylinder in the form of a hollow cone, while those equipped with hole type nozzles direct fuel toward the walls of the engine cylinder or toward the piston head in comparatively heavy streams or solid jets.

. It is the purpose of my invention to provide means for delivering to the cylinder of an internal combustion engine a fuel charge which may be mixed with air in the cylinder prior to ignition and at the same time to overcome those disadvantages inherent in previous types of fuel injectors. In accordance with my invention, a fuel injector for an internal combustion engine is provided with a discharge nozzle equipped with a plurality of orifices from which fuel will be delivered into the engine cylinder in the form of a generally pear-shaped solid cloud of fuel particles.

The phrase generally pear-shaped solid cloud of fuel particles used herein to describe the fuel charge delivered by the nozzle which I have invented means fuel particles distributed throughout a body having a convex outer end and conical walls (illustrated in Fig. 4 of the drawing) as distinguished from fuel distributed over the surface of a cone as in the caserof the well-known hollow conical spray. v

The form in which I now prefer to practice my invention is illustrated in the accompanying charge delivered to the cylinder of an 4internal combustion engine in vaccordance with my invention. Y

The fuel injector illustrated in the drawing is of the hydraulically operated type and comprises a shank I0 and a nozzle II firmly fixed tc the shank by means of a cap I2. The nozzle II is normally closed by valve I4 whose stem I5 extends along the axis of nozzle II and shank III. The valve I4 is urged against its seat I5 by means of-a coil spring I1 compressed between the head I 3 of valve stem I5 and a plug I9 which is covered by a protective cap 20. A conduit 22 which leads to a conventional fuel pump (not shown) communicates through passageway 23 with pressure chamber 24 in nozzle-I I.

The valve I4 `is hydraulically operated by the fuel which at predetermined intervals is forced by the fuel pump through passageway 23 to the pressure chamber 24. When the pressure of the fuel in chamber 24 exceeds that exerted by spring I1, valve I4 is lifted from its seat and the fuel flows through passageways in the tip of the nozzle II until the pressure of the fuel is reduced sufficiently to permit spring I1 to seat valve I4.

The fuel injector nozzle illustrated contains a cone-shaped valve I4 whose seat I5 is of a complementary conical shape. An expansion chamber 25 having an outwardhr flaring conical wall 21 is interposed between valve seat I4 and the tip 28 of the fuel injector nozzle. The conical valve seat I6 and the conical wall 21 of expansion chamber 25 are provided by the member 29 fixed in nozzle Il. It is to be understood, however, that valve seat I6 and conical wall 21 may be formed integral with the fuel injector nozzle II. The shape of chamber 25, provided by the conical wall 21, is such that fuel entering expansion chamber 25 from pressure chamber 24 expands, thus commencing latomization of the fuel.

'I'he tip 28 is provided with a fine axial passageway 3| terminating in orifice 3|' and with staggered sets of oblique passageways 32, 33 and 34 arranged in concentric circles around theaxis of the injector and which terminate in orifices 32', 33' and 34' respectively. These passageways lare projected from the axis of the injectorA increase progressively and the diameters of those oblique passageways preferably decrease progressively in size. The differences in the sizes of the angles at which the pasageways 3|, 32, 33 and .3l are Yprojected from the iniector cause fuel to be sprayed therefrom in nne contiguous streams which form a solid conical cloud of fuel particles.

The conical shape of the valve Il and of valve seat I6 causes fuel to enter expansion chamber 25 in the form of a hollow cone whose apex is located within expansion chamber 25 and along the axis of the injector. As a consequence, fuel flows at the greatest velocity through the part of expansion chamber 25 which isalong the axis of the injector and thence through nozzle passageway 3|. The velocity of the fuel in chamber 25 diminishes progressively as the distance from the axis of the injector increases. Consequently, fuel sprayed from the outer orifice 32', 33 and 34 will travel lesser distances in the engine cylinder so that the solid conical cloud of 'fuel particles has a convex end surface. may be increased by the progressive reductions in the diameters of the outer circular sets of orilces 33 and 34' as illustrated in Figs. 2 and 3 of the drawing. The fuel is thus sprayed from nozzle Il in the form of Aa generally pear-shaped solid cloud of fuel particles as illustrated i'n Fig. 4 of the drawing.

The fuel injector which I have invented is especially useful in connection with an internal combustion engine of the type which forms the subject-matter of my U. S. Patent No. 2,151,698, wherein the fresh air with which the fuel is to be mixed is whirled rapidly around the axis of ythe engine cylinder. When my injector is mounted at the top, and along the axis of, the cylinder 40 of such an engine, the fuel particles of the radially advancing cloud ('see Fig. 4) will have imparted to them the whirling motion of the air in the cylinder, so that they will, by centrifugal action, be spread toward the walls of cylinder 40 thus insuring a very thorough admixture of those `fuel particles with air in cylinder This eilect y I and, by proper timing of ignition, the mixture of fuel and air may be ignited beforev the fuel reaches the walls of cylinder 40 or the head of piston 4|.

Itis to be understood that various modifications may be made in the specific embodiment of my invention described above without departing from the spirit of my invention as defined in the appended claims.

`What I claim is:

1. In a fuel injector for internal combustion engines, a discharge nozzle having a plurality of sets of orifices disposed around the axis gf the injector in concentric circles and means for spraying fuel from said orifices at velocities which diminish progressively as the distance of the orifices from said axis increases. 2. In a fuel injector for internal combustion engines, a discharge nozzle having radially spaced orifices disposed about the axis of the nozzle, wherein the diameters of the orifices decrease progressively with increases in the distance of said orices from said axis.

'3. In a fuel injector for internal combustion engines, a discharge nozzle having a tip provided withva plurality of radially spaced orifices Whose diameters decrease progressively with increases in their distance from the axis of the injector, a valve, and a seat for said valve, spaced from the tip to provide an expansion chamber between the valve and said tip. y

4..In a fuel injector for internal combustion engines, a nozzle having a plurality of `sets of oblique4 discharge passageways disposed in concentric circles, wherein the respective circular sets of discharge passageways are projected from the axis of the injector at acute angles which increase in size progressively with increases in the distance of said circular sets from said axis.

WILLIAM HARPER, JR. 

